Pliers with rack and toothed lever means coming into meshing engagement when the jaws contact a workpiece



3,224,303 PLIERS WITH BACK AND TOOTHED LEVER MEANS COMING INTO MESHING ENGAGEMENT WHEN THE JAWS CONTACT A WORKPIECE Filed July 16, 1964 P. R. GIROUX Dec. 21, 1965 3 Sheets-Sheet l M f m y M PierIe/ R Dec. 21, 1965 P. R. GIROUX 3,224,303 PLIERS WITH BACK AND TOOTHED LEVER MEANS COMING INTO MESHING ENGAGEMENT WHEN THE JAWS CONTACT A WORKPIEGE Filed July 16, 1964 3 Sheets-Sheet 2 Pierre KG/ROUX ATTORNEKS Dec. 21, 1965 P. R. smoux 3,224,303

PLIERS WITH RACK AND TOOTHED LEVER MEANS COMING INTO MESHING ENGAGEMENT WHEN THE JAWS CONTACT A WORKPIECE Filed July 16, 1964 3 Sheets-Sheet 5 Pierre/EG/RM/X ATTORNEYS United States Patent C) PLIERS WITH RACK AND TOOTHED LEVER MEANS COMING INTO MESHING ENGAGE- MENT WHEN THE JAWS CONTACT A WORK- PIECE Pierre R. Giroux, Laviolette, Quebec, Canada, assiguor of ten percent to Omer Veillette, La Tuque, Canada Filed July 16, 1964, Ser. No. 383,002 10 Claims. (Cl. 81--343) The instant invention relates to a pliers of the power type, that is, of the type wherein increased mechanical clamping power is available between the jaw members of the pliers by special leverage action of the operating arms.

A main object of the invention resides in the provision of a pliers of the above-mentioned type which is very rapid in operation as the actual clamping power is applied only after the jaw members sense a resistance therebetween. Only at that moment can the full power of the hand be applied to the jaw members, and that with increased leverage action as will hereinafter be more fully described.

Yet another object of the. invention resides in the provision of a tool of the above type of simplified structure, eflicient in operation and low in manufacturing cost which, furthermore, may include an optional locking device for use when a certain article is to be retained between the jaw members in clamping engagement therewith.

, Still another object of the invention lies in providing a pliers of the power type with means adapted to reduce any back lash between the normally loose operating lever arm and one of the jaw members whereby to ensure immediate clamping action upon relative movement between the two lever arms after the jaw members have been arrested by a resisting element located therebetween.

Further objects and other advantages of the invention will become apparent from the following description having reference to the appended drawing wherein:

FIG. 1 is a perspective view of a pliers made according to the invention;

FIG. 2 is a side elevation view of the pliers of the invention in open position; .i

FIG. 3 is another side elevation view of the pliers, as the jaw members are arrested in their rotation by a resisting element therebetween;

FIG. 4 is a side elevation view of the pliers with the clamping movement already begun;

FIG. 5 is a partial elevation view, on an enlarged scale, of the pliers with parts taken away to show the inner structure thereof; the parts being in open position;

FIG. 6 is a elevation view similar to that of FIG. 5 but illustrating the pliers during the clamping process;

FIG. 7 is an exploded view of the embodiment of the pliers of the invention as shown in FIGS. 1 to 6;

FIGS. 8 and 9 are side elevation views of a second embodiment of the invention in open and closed positions thereof.

Basically, the power pliers of the invention comprise a first and a second jaw member pivotally interconnected for movement toward and away from one another; a first operating lever arm integral with said first member; said first jaw member being formed with a toothed rack; a plate pivotally mounted on said second member; a second operating lever arm, for and separate from said second member, pivotally mounted on said plate and formed, at one end thereof adjacent said toothed rack, with a circular gear segment adapted to mesh with the said rack. The invention is further particularly characterized by the provision of means on the second jaw 3,224,303 Patented Dec. 21, 1965 member and on the plate cooperating to limit pivotal displacement of the plate and operative, upon relative movement of the arms toward one. another and upon pivotal movement of the jaw members being arrested by a resisting element therebetween, to cause meshing of the gear segment and rack, whereby further relative movement of the arms causes riding of the gear segment on the said rack and increased force on the element between the said members.

More specifically, and as illustrated in FIGS. 1 to 7, the invention is formed of a first jaw member 1 merging into a central part 3 formed, along a rear edge thereof, with an arcuate toothed rack 5 and having an integral elongated lever arm 7 projecting away from the said central part 3 at one edge thereof.

A second jaw member 9 having a rear end 11, corresponding to central part 3 of first jaw member 1, formed as a fork to thus straddle the said central part. For that reason, it will be noted (FIG. 7) that central part 3 is thinner than the first jaw member 1 so that as forkshaped rear end 11 fits and straddles over central part 3, jaw members 1 and 9 face one another in cooperating relationship.

The jaw members are here shown with facing working outlines in the form of conventional clamping indentations and cutting edges. Other conventional working outlines may of course be used.

I aw members 1 and 9 are pivotally interconnected by means of a first pin means 13 to be referred to again later in more details.

A pair of cheek plates 15 are pivotally mounted on the second jaw member 9, on each side thereof, by means of a stud 17 integral with member 9 and loosely fitting in a suitable aperture 19 (FIG. 7) through each plate 15. Plates 15 are retained thereon by riveting the end of studs 17 or by any other suitable means.

In the particular embodiment illustrated in FIGS. 1 to 7, plates 15 are also provided, forwardly thereof, with an elongated slot 21 slightly arcuate with the curvature thereof having the axis of aperture 19 as a center. In combination vw'th slots 21 of plates 15 is a hole 23 through central part 3 of first jaw member 1. The aforementioned first pin means 13 extends through hole 23 of first jawmember 1, hole 22 of second jaw members and slots 21 and is seen to comprise a pin 25 provided, at each end thereof, with a circumferential groove 27 adapted for the reception of a horseshoe lock ring 29 having an outer contour greater than slots 21 whereby to retain plates 15 and central part 3 in the predetermined relationship illustrated in FIG. 1.

A second operating lever arm 31 is pivotally mounted on and between the two plates 15 by means of second pin means 33 comprising a cylindrical stud 35 extending through holes 37 of plates 15 and having a threaded bore for the reception of a locking screw 39. It will be noted that the end of second lever arm 31 corresponding to second pin means 33 is formed as a gear segment 41 adapted to mesh with the toothed rack' 5 of the central part 3.

A series of indentations 43 is provided along an arcuate rearward edge of each plate 15. The said indentations 43 being intended for the reception of the sharp ends 45 of a generally fork-like locking pawl 47 pivotally mounted, centrally thereof, on pins 49 provided on each side of second lever arm 31. Also mounted on the said pin 49 is a generally U-shaped pawl-pivoting member 51 having a pair of branches with curled ends fitting over pins 49 and a central bottom member adapted to sit over the lock" ing pawl 47.

- Biasing means is also provided for normally keeping the gear segment 41 of lever arm 31 out of engagement with the toothed rack 5. This biasing means is a spring 53 having a pair of coiled parts 55 loosely mounted over studs 35 of second lever arm 31 and retained thereon by means of screws 39, or any other suitable means such as a horseshoe lock ring. The wire forming each coiled part 55 extends rearwardly to join the other coiled part to thus form a U-shaped part 57 while the other end of the wire of each coil part 55 extends forwardly in the form of an L-shaped part 59. As best illustrated in FIG. 1, each L-shaped part 59 has a bent end hooking into a rearwardly facing lug 61 provided on the second jaw member 9 while the U-shaped part 59 resiliently sits over the pawl pivoting member 51.

The vertical branch of L-shaped part 59 is bent back ward toward pivot means 33 and rest against lug 61 in pre-stressed condition whereby to force plates 15 in clock wise rotation about pin means 17. Similarly, in inoperative position of the pliers, the U-shaped part is pre' stressed whereby to bias said second arm clockwise.

With the above description in mind, the operation of the power pliers of the invention will now be described with particular reference to FIGS. 1 to 6.

In FIG. 2, the pliers is shown in wide open position with lever arms 7 and 31 spread apart, the latter being further pressed outwardly by means of spring 53. Furthermore, it should be noted that pawl pivoting member 51 has been shifted leftward and under the action of spring 53 forces the locking pawl 47 to pivot counterclockwise thus disengaging the sharp ends 45 of the pawl from the indentations 43. However, a shoulder 63 is provided at the beginning of indentations 43 and is of such a size as to cause abutment of sharp ends 45 thereon whenever pawl 47 is released from the said indentations 43. Further anticlockwise rotation of pawl 47 would free ends 45 from shoulder 63 and allow further movement of arm 31.

Also to be noted is the fact that spring 53 has pivoted both plates 15 clockwise about the axis of the plates pivot means 17, as said above. In this position, the jaw members pivot means 13 sits in the bottom of grooves 21.

Assuming that it is intended to forcibly clamp a solid element 65 between jaws 1 and 9 and holding it locked in clamped position, the pawl pivoting member is shifted rightward thus causing pivoting of locking pawl 47 clockwise for engagement of the sharp end thereof with indentations 43 (this is the situation in FIG. 3).

In the position shown in FIG. 2, whenever the two lever arms 7 and 31 are moved relatively to one another by pivoting about the jaw members pivot means 13, be cause of the action of spring 53, second lever arm 31, plates 15 and second jaw member 9 move as a unit with, as aforesaid, jaw members pivot means 13 resting in the bottom of slots 21.

This situation will hold until a resistance is met as in the form of the solid element 65. This is then the situation of FIG. 3. At that moment, the strength of spring 53, suitably chosen, is no longer suflicient to prevent the pivoting anticlockwise of plates 15 about pivot means 17 thus bringing the gear segment 41 in engagement with the toothed rack and abutment of pivot means 13 against the top of slots 21. This is the situation illustrated in FIGS. 4 and 6, the latter particularly illustrating the angular extent of pivoting of plates 15.

It should be understood that, from this time on, any further relative movement between the lever arms 7 and 31 will cause riding of the gear segment 41 on the toothed rack 5 resulting in further relative pivoting of the jaw members 1, 9 toward one another; the power developed depending on the ratio of the radius of the toothed rack 5, the center of which is the axis of pivot means 13, and the radius of gear segment 41, the center of which is the axis of pivot means 33.

Simultaneously as the two arms move closer together, the sharp ends 45 of locking pawl 47 ride on indentations 43, being retained therein by means of spring 53. Consequently, any return action of the two lever arms is prevented and the jaws are rigidly held in clamped position.

FIGS. 8 and 9 are illustrated to particularly show that the means limiting pivotal action of plates 15 is not necessarily provided by slots such as 21 of FIGS. 1 to 7. In this instance, the said means is formed of a sleeve 67 in tegral with plates 15', the said sleeve having a threaded bore into which is threaded an abutting pin 69 adapted to come against a flat land 71 provided along an edge of the second jaw member 9'. The afore-described assembly will define a first limit for the pivotal action of plates 15, the second limit being afforded by a second pin 73 suitably mounted on another location on plates 15 whereby to abut another edge of the second jaw member 9. Pin 73 may likewise be adjustable whereby to vary this limit as well as the first limit defined by pin 69 and land 71.

It will have been noted that no spring is illustrated in this embodiment. Such a means is of course to be pro vided whereby to obtain release of the gear segment 41 from the toothed rack 5 and this may be done by locating a coil spring between land 71 and sleeve 67.

In the embodiment of FIGS. 8 and 9, the tool being a cutter, there is of course no need for locking the tool in clamping position as in the previous embodiment. In dentations 43' shown on an edge of plates 15 are here illustrated only to show that the back lash between the second lever arm 31 and the toothed rack 5 may be adjusted and also to prevent loosening of the said lever arm 31. For that purpose, a locking pawl 47 is pivotally mounted on the said second arm 31' and adjustable to rest on any of indentations 43.

An added feature of this embodiment resides in the pro vision of a screw 75 adjustably threadedly mounted on the edge of the second lever arm 31 facing the first lever arm 7'. As illustrated in FIG. 9, screw 75 is intended to prevent overriding of second lever 31 which would cause clamping of the finger between two levers and possible injury thereto.

The above described embodiments should not be taken as limitative and the invention which should only be construed from the appended claims.

I claim:

1. Power pliers comprising:

(a) a first and a second jaw member pivotally interconnected for movement toward and away from one another;

(b) a first operating lever arm integral with said first member; said first jaw member being formed with a toothed rack;

(c) a plate pivotally mounted on said second member;

(d) a second operating lever arm, for and separate from said second member, pivotally mounted on said plate and formed, at one end thereof adjacent said toothed rack, with a circular gear segment adapted to mesh with the said rack, and

(e) means on said second jaw member and on said plate cooperating to limit pivotal displacement of said plate and operative, upon relative movement of said arms toward one another and upon pivotal movement of the jaw members being arrested by a resisting element therebetween, to cause meshing of said gear segment and rack, whereby further relative movement of said arms causes riding of said gear segment on said rack and increases force on said element between said members.

2. Power pliers comprising:

(a) a first and a second jaw member and pivot means interconnecting said members for movement toward and away from each other;

(b) a first operating lever arm integral with said first member; said first jaw member being formed with a toothed rack;

(c) a plate on each side of said second jaw member and pivot means connecting said plates to said second jaw member to pivot about a common axis;

(d) a second operating lever arm for and separate said arm on and between said plates; said second arm being formed with a circular gear segment adapted to mesh with said rack;

(e) the axes of said jaw members pivot means, said plates pivot means and said second arm pivot means being the three apices of a triangle, and

(f) means on said second jaw member and on said plate cooperating to limit pivotal displacement of said plate and operative, upon relative movement of said arms toward one another and upon pivotal movement of the jaw member being arrested by a resisting element therebetween, to cause meshing of said gear segment and rack, whereby further relative movement of said arms causes riding of said gear segment on said rack and increases force on said element between said members.

3. Power pliers as claimed in claim 2, further including:

(g) means biasing said gear segment out of engagement with said rack, and

(h) means locking said jaw members in clamp position.

4. Power pliers comprising:

(a) a first and a second jaw member and pivot means interconnecting said members for movement toward and away from each other; said first jaw member being formed with an arcuate toothed rack;

(b) a first operating lever arm integral with and projecting away from said first member;

(c) a plate on each side of said second jaw member and pivot means connecting said plates to said second jaw member to pivot about a common axis;

((1) said plates being each provided with a slot therethrough, through which said jaw members pivot means extend whereby said slot limits pivoting of said plates about said common axis;

(e) a second operating lever arm for and separate from said second member and pivot means mounting said arm on and between said plates; said second arm being formed with a circular gear segment adapted to mesh with said rack;

(f) the axes of said jaw members pivot means, said plates pivot means and said second arm pivot means being the three apices of a triangle, and

(g) resilient means biasing said second arm and gear segment away from said toothed rack.

5. Power pliers as claimed in claim 4, wherein said resilient means is a wire spring loosely coiled around said plates pivot means and having a pre-stressed L- shaped end abutting a lug on said second jaw member and a second pre-stressed end abutting said second arm to pivot the said arm so that said segment is biased away from said rack.

6. Power pliers comprising:

(a) a first and a second jaw member and pivot means interconnecting said members for movement thereof toward and away from one another; said first member being formed, rearwardly thereof, with an arcuate toothed rack generally concentric with said pivot means;

(b) a first operating lever arm integral with and projecting away from said first member and said toothed rack;

(c) a plate on each side of said second jaw member and pivot means connecting said plates to said second jaw member to pivot about a common axis;

(d) said plates being each provided with a slot therethrough, through which said jaw members pivot means extend whereby said slot limits pivoting of said plates about said common axis;

(e) a second operating lever arm for and separate from said second member and pivot means mounting said arm on and between said plates; said second arm being formed at one end with a circular gear segment adapted to mesh with said rack;

(f) the axes of said jaw members pivot means, said plates pivot means on said second arm pivot means forming the three apices of a triangle with the axis of said plates pivot means located away from the jaw of said second jaw member in relation with a line joining the other two axes;

(g) resilient means rocking said plates about said plates pivot means to bias said second arm and gear segment away from said toothed rack; said plates rocking to one limit set by said slot (item (1);

(h) abutting means limiting movement of said second arm under the bias of said resilient means, whereby as said arms are moved toward one another, said second arm, plates and second jaw move as a unit under the bias of said resilient means until resistance in the form of an element between the jaws of said jaw members is met at which time said plates rock about the pivot axis thereof to the other limit set by said slot, while said gear segment comes in meshing engagement with said toothed rack, then further relative movement of said arms causes riding of said gear segment on said rack and increases force on said element between said members.

7. Pliers as claimed in claim 6, including indentations on an edge of each of said plates and a locking pawl having sharp ends pivotally mounted on said second lever whereby when said pawl is pivoted in a predetermined rotation, said sharp ends engage in one of said indentations, and a lever at the end of said pawl opposite said sharp end to release said pawl.

8. Pliers as claimed in claim 7, wherein said abutting means is a flange at the beginning of said indentations.

9. Pliers as claimed in claim 7, wherein said pawl is provided with a latching member pivotally mounted on said means pivotally mounting said locking pawl on said second lever arm; said latching member movable in two positions to engage and disengage said sharp end of said pawl with and from said indentations.

10. Pliers as claimed in claim 9, wherein said resilient means is a wire spring loosely coiled around said plates pivot means and having a first end thereof abutting a lug on said second jaw member and a second end bearing on said pawl latching member to retain said pawl into or out of engagement with said indentations.

References Cited by the Examiner UNITED STATES PATENTS 1,546,139 7/1925 Leveque 81-365 1,625,615 4/1927 Kuttes 81-365 1,915,404 7/1933 Clifton 81-365 2,906,155 9/1959 Miller 81-343 FOREIGN PATENTS 28,974 AD/ 1909 Great Britain.

WILLIAM FELDMAN, Primary Examiner.

firorn said second member and pivot means mounting 

1. POWER PLIERS COMPRISING: (A) A FIRST AND A SECOND JAW MEMBER PIVOTALLY INTERCONECTED FOR MOVEMENT TOWARD AND AWAY FROM ONE ANOTHER; (B) A FIRST OPENING LEVER ARM INTEGRAL WITH SAID FIRST MEMBER; SAID FIRST JAW MEMBER BEING FORMED WITH A TOOTHED RACK; (C) A PLATE PIVOTALLY MOUNTED ON SAID SECOND MEMBER; (D) A SECOND OPERATING LEVER ARM, FOR AND SEPARATE FROM SAID SECOND MEMBER, PIVOTALLY MOUNTED ON SAID PLATE AND FORMED, AT ONE END THEREOF ADJACENT SAID TOOTHED RACK, WITH A CIRCULARR GEAR SEGMENT ADAPTED TO MESH WITH THE SAID RACK, AND (E) MEANS ON SAID SECOND JAW MEMBER AND ON SAID PLATE COOPERATING TO LIMIT PIVOTAL DISPLACEMENT OF SAID PLATE AND OPERATIVE, UPON RELATIVE MOVEMENT OF SAID ARMS TOWARD ONE ANOTHER ANDUPON PIVOTAL MOVEMENT OF THE JAW MEMBERS BEING ARRESTED BY A RESISTING ELEMENT THEREBETWEEN, TO CAUSE MESHING OF SAID GEAR SEGMENT AND RACK, WHEREBY FURTHER RELATIVE MOVEMENT OF SAID ARMS CAUSES RIDING OF SAID GEAR SEGMENT ON SAID RACK AND INCREASES FORCE ON SAID ELEMENT BETWEEN SAID MEMBERS. 